Pros
Above all, fabulous people. In 6 years at Deltek I only met a few jerks, and frankly, they got managed out. Deltek has a great niche, and is a cash-generating machine, which is good for job security. Average to good benefits. Average to good salary-wise. Outstanding flexible work arrangements (work from home, etc), tons of clubs, charity work, intramural sports, if you're into that sort of thing. Lots of communications with employees...lots of access to top management. Clearly articulated company values. There's a feeling of being on a winning team.
Cons
For the past several years, Deltek has been acquiring companies at the rate of about two a year. What with all the integration and organizational change, it can be a little unsettling if you're into stability. There's a lot of cheese-moving. Acquisitions are balanced with intermittent down-sizings, which make people leery. Total net number of employees hasn't changed despite numerous acquisitions. Promoting from within and career-paths continue to be a weakness.